1. Field of the Invention
The present invention relates to an apparatus for dividing, compressing and transmitting video data that improves encoding efficiency without requiring preferential transmission of basic data.
2. Description of the Related Art
In an environment where the transmission quality largely varies (particularly, in an environment where the transmission speed varies largely), a method for enabling reception of images having an image quality corresponding to its quality has been heretofore studied, and as one method, application of scalability encoding has been tried. Conventional scalability encoding (hereinafter, referred to as “first scalability encoding”) is divided largely into the followings:
1) time scalability capable of selecting the resolution in the direction of time stepwise;
2) space scalability for changing the space resolution;
3) data partitioning for dividing the frequency elements; and
4) SNR scalability for selecting encoding distortion stepwise.
However, these scalability encoding makes normal reception of the basic data on a reception side a precondition. Therefore, on a transmission side, it is necessary to transmit the basic data preferentially.
On the other hand, scalability encoding in which the above-described basic data is not necessarily transmitted preferentially (hereinafter, referred to as “second scalability encoding”) has been proposed. This method is referred to as “flat multi-scalable encoding” and uses transmission using a redundant system. This method, however, transmits data encoded respectively independently, via a corresponding channel, respectively, and the reception side performs processing for averaging these data. Therefore, there is a problem in that it is not sufficient in view of the encoding efficiency.
As described above, the first scalability encoding method has a problem in that the basic data must be transmitted preferentially, and the second scalability encoding method has a problem in that the encoding efficiency is not sufficient.